Re: sata_dwc_460ex driver

[Mason <slash.tmp@free.fr>]

On 27/05/2016 18:20, Måns Rullgård wrote:

> Mason wrote:
> 
>> I'm working on a SoC which embeds an IP block from Synopsys labeled
>> Synopsys DesignWare Cores Serial ATA AHCI Core, aka DWC_ahsata
>> (DWC SATA AHCI Host 6Gb/s AXI Interface).
>>
>> Would the sata_dwc_460ex driver support this DWC_ahsata hardware?
>>
>> I suppose I would also need to enable AHCI support, right?
>>
>> What is the difference between SATA_AHCI and SATA_AHCI_PLATFORM ?
>>
>> SATA_AHCI          = 971db06e09231
>> SATA_AHCI_PLATFORM = 1c2a49f61785e
>>
>> If I understand correctly, SATA_AHCI is for platforms with a PCI bus,
>> while SATA_AHCI_PLATFORM is for other platforms. I probably want the
>> latter then?
>>
>> On the analog side, the SATA PHY is also made by Synopsys.
>> Do I need to enable a specific driver?
>> I didn't see anything relevant in drivers/phy
>>
>> (The documentation mentions 11 registers for tweaking the controller,
>> but maybe it's the boot-loader's job to set this up correctly?)
> 
> The sata_dwc_460ex driver can be made to work with the tango3/4 chips.

I'm talking about tango5. It's not the same controller as tango3/4.
(They use different Synopsys DesignWare controllers.)

> You need a dmaengine driver (I've written one for tango3, needs slight
> tweaking for tango4) and some additions to the SATA driver to handle the
> DMA glue logic (I have unpublished code for this as well).  There are a
> bunch of fixes for the SATA driver currently in linux-next, and I was
> planning to take another look at supporting tango3/4 once these hit
> mainline (4.7-rc1 most likely).

FWIW, it seems like tango4 is low-priority internally ATM.

> A driver for the PHY is probably a good idea, even if the boot loader
> does some configuration, since this allows it to be powered down when
> not in use.

How come there are so few phy drivers in drivers/phy if most devices
would typically require one?

Regards.